Catalytic Reductive Homocoupling of Benzyl Chlorides Enabled by Zirconocene and Photoredox Catalysis

The bibenzyl skeleton is prevalent in numerous natural products and other biologically active compounds. Radical homocoupling provides a straightforward approach for synthesizing bibenzyls in a single step, with the reductive homocoupling of benzyl halides undergoing extensive development. Unlike benzyl bromides and other tailored pre-cursors used in visible light-mediated homocoupling, benzyl chlorides offer greater abundance and chemical stabil-ity. Nevertheless, achieving chemoselective cleavage of the C–Cl bond poses significant challenges, with only a limited number of studies reported to date. Herein, we demonstrate a catalytic reductive homocoupling of benzyl chlorides facilitated by zirconocene and photoredox catalysis. This cooperative catalytic system promotes C–Cl bond cleavage in benzyl chlorides under mild conditions and supports the homocoupling of a wide range of benzyl chlorides, includ-ing those derived from pharmaceutical agents. Our preliminary mechanistic investigations highlight the pivotal role of hydrosilane in the catalytic cycle.